Device to modify the pitch between pushers according to the length of the product

ABSTRACT

The apparatus is formed of two identical devices (A, A′) installed mirror image-fashion, each of which is equipped with a pressure bar ( 19, 19 ′) fitted to overhang the relevant lateral toothed conveyor belts (T T′) which move and recircle the said bars, and which are in their turn activated by relevant motors ( 8, 8 ′) with electronic speed and phase control governed by one programmable processing unit ( 26 ). When the length of the products (P) is less than the length of the straight branches of the conveyors moving the said bars, the two devices are installed mirror-image fashion, with the axles of the pulleys of one conveyor aligned with those of the corresponding pulleys of the other conveyor. In this position, the bars ( 19, 19 ′) of the two devices alternate in taking, moving foward by pushing and the final placing of the products in the workstation (K). However, when the length of the products exceeds the length of the said conveyors moving the bars, the possibility is offered of acting on both means, allowing anticipation of the longitudinal position of one device in relation to the other, so that the products are firstly taken by the bar ( 19 ′) of device (A′) working in advance and are transferred from it in phase to the bar ( 19 ) of the downstream device (A), which in turn provides for the transfer and phased placing of the product in the workstation (K).

[0001] The invention concerns a variable pitch apparatus for thrust and phase feed of products to a workstation. In particular, but not exclusively, the invention finds industrial use in a machine of so-called flow-pack type for packing paper rolls or paper and board products in heat-weldable film packaging. The apparatus operates subsequently on paper rolls which are fed in phase by means of a well-known type and pushes these same products in phase into axial tubing mandrel of the thermoplastic film material unwound by a bobbin and which in passing over the said former mandrel is formed into a tube for wrapping the products and is then welded longitudinally to finish off the tubular packaging which is subject downstream of the mandrel to the action of transverse means of cutting and/or tearing for the reciprocal separation of the packagings which is then closed at the ends by other means.

[0002] To carry out functions of this type so-called recirculation transfer devices are known, whose thrust units are connected to pairs of adjoining chain conveyors usually connected to a single motive power source, one directly and the other with the intervention of a phase shifter, by acting on which it is possible to vary the distance between the device's thrust units to adapt their pitch at a different pitch and the varying length of products to be packaged. These devices are structurally complex, bulky and have little flexibility for adaptation to varying demands of use. Similar recirculation transfer devices are described in U.S. Pat. No. 5,213,198, for example.

[0003] The invention is meant to obviate known technical limits with a variable pitch thrust feed apparatus formed of two adjoining identical devices installed mirror-image fashion, each of which is equipped with a thrust bar fixed to overhang a relevant positive type lateral conveyor, e.g. with toothed belts, which moves the recirculating bar and which is in turn moved by a relevant electronically controlled speed and phase motor. The motors of the two conveyors are connected to a processing unit which may be easily programmed to adapt the working of the apparatus to varying work requirements. When the length of the products is less than the length of the straight and working branches of the conveyors moving the said bars, the two devices are placed side by side mirror-image fashion with the pulleys of one lateral conveyor aligned with those of the corresponding pulleys of the other conveyor. In this condition the bars of the two devices alternate in taking, moving forward by thrusts and finally placing the products in the packaging station. However, when the length of the products exceeds the length of the said active branches of the conveyors moving the bars, the possibility is given of acting on the means allowing anticipation of the longitudinal position of one device in respect of the other, so that the products are first taken by the bar of the device working in advance and are transferred thereby in phase to the bar of the device downstream, which in turn provides for the transfer and phased placing of the product in the packaging station.

[0004] Major characteristics of the invention and the benefits derived therefrom will appear more obvious from the following description of a preferred form for its implementation, illustrated by way of non-restrictive example in the figures of the three appended sheets of drawings in which:

[0005]FIGS. 1, 2 and 3 illustrate the apparatus respectively in front elevation, side elevation and in perspective, as well as in the phase feed condition for products of a length less than that of the active branches of the conveyors of the two recirculation devices comprising this apparatus;

[0006]FIG. 4 illustrates with parts in section, the constraint on one of the toothed conveyor belts of the apparatus from one of the vertical connecting rods with the relevant thrust bar;

[0007]FIGS. 5 and 6 illustrate the equipment in the plant respectively from above and in side elevation, as well as in the phase feed condition for products of a length greater than that of the active branches of the conveyors of the two recirculation devices of the said apparatus.

[0008] The apparatus comprises two identical devices placed opposite one another mirror-image fashion indicated by A and A′. To simplify the description reference shall now be made to device A, which is composed of a vertical plate 1, which supports revolving at right angles a pair of horizontal axles, 2, 102 lying on an ideal vertical plane and protruding from the opposing sides of the said plate to carry keyed onto the side turned towards the other device A′, toothed pulleys of equal diameter 3, 103 and to carry keyed on the other side of the said plate 1, toothed pulleys 4, 104 of equal diameter and smaller, for example than the previous pulleys and on which is fed a toothed belt 5 controlled by a tensioner 6 supported by an adjustable bracket 106 and fed on the toothed pulley 7 keyed to the shaft of a motive power set 8, which is in turn flanged on a bracket 9 with an L-shaped plate fixed to the plate 1. The motive power set 8 is equipped with an electric motor with electronic speed and phase control, e.g. of brushless type. Because of the kinematic connected to the set 8 described, the axles 2, 102 rotate in the same direction and at the same speed. On pulleys 3, 103 the toothed belts 10, 110 with identical characteristics are fed, fed on corresponding pulleys 30, 130 identical to those 3, 103 which are supported and rotate on a bracket 11, e.g. of T-shape, fixed to the plate 1 with screws 12 and with slot holes 13 allowing the horizontal adjustment of the said bracket to provide the said belts with the necessary longitudinal tension. The toothed belts 10, 110 produce the recirculation conveyor T of device A, are suitably spaced from one another and their straight branches are parallel to the product's direction of travel (see below).

[0009] At a point of the branch higher (or lower) than the belt 10 and at a corresponding point of the branch higher (or lower) than the belt 110 (points aligned vertically with each other) are fixed by a known solution transverse pins 16 which expediently protrude from the side of the belt opposite that turned towards the plate 1. From the detail of FIG. 4 it is noted for example that the pins 16 are equipped on their sides with drilled appendages 116 which are fixed to the belt 10 or 110, e.g. by means of screws 15 screwed into small guides 14 housed in holes formed and obtained into one tooth of this belt. The pins 16 may themselves be revolving in the part which links them to the belt or may be fixed and in this instance are fitted with a coupling revolving at intermediate points of a flat and vertical connecting rod 17, produced preferably in light alloy and provided with lightening holes 18 so as to have a limited weight. The lower end of the connecting rod 17 is conveniently tapered as shown by 117 in FIG. 2 and above this is fixed perpendicularly and overhanging a horizontal bar 19 preferably comprised of a idle roller, which conveniently protrudes at the front from the said end 117 which is turned towards the travelling direction of the product. By virtue of the connection to the synchronised conveyor belts 10, 110, the bar 19 is activated by a recircling movement with a straight displacement of travel in the low position and return in the raised position. To avoid the transom 19 making undesirable oscillating movements, provision has been made for the sections of the connecting rod 17 protruding above and below the pairs of transport belts 10, 110 run in straight, parallel guides 20, 120 integral to brackets 21, 121 fixed to the lower and upper ends of the plate 1 and provision is made for the co-operation between these connecting rods 17 and the aforementioned guides takes place with the intervention of material with a low friction coefficient, e.g. with coatings of suitable plastic material 22 fixed to the opposing faces of the parts of the connecting rod 17 working together with the said guides.

[0010] The components of device A′, which are identical to those described for device A, are shown with identical numbers and with the addition of the “prime” symbol (′). From FIG. 1 it is apparent that devices A and A′, as described, are arranged so that their thrust bars 19, 19′ operate transversely and within a guide channel C defined lower down by a fixed surface or by a carrier which moves at a speed lower than that of the belts 10, 110 and defined lower down by guide rails whose relative position may be changed to vary the dimensions of the product P to be handled. For the adaptation for carrying products of different dimensions, it is for example foreseen that these devices A and A′ are fixed with their plates 1, 1′ on relevant horizontal runners 23, 23′ running on corresponding straight guides 123, 123′ parallel to the bars 19, 19′ of the same devices under discussion and of these guides one is fixed to a support frame shown schematically with 24, whilst the other is fitted, for example, on an orthogonal and horizontal runner 25, therefore parallel to the channel C, which in turn runs on a corresponding guide 125 fixed to a support frame 24′. It is understood that the linking order of the guides 123′ and 125 to the frame 24′ may be inverted compared with the solution shown. Appropriate means of manual and remotely controlled operation are foreseen for working the runners 23, 23′ to change the distance between the devices A and A′ upon variation of the width of the product to be conveyed, as shown by the arrows F and F′, and to work the runner 25 as shown by the arrow F′ to change the relative horizontal position of these devices A and A′ upon variation of the length of the product P (see below).

[0011] The motors 8 and 8‘of the devices A and A’ are connected to a processing unit 26 equipped with at least one input 126 to receive synchronism and phase information and other data from components of the plant in which the apparatus concerned in used and which is connected in 226 to a programming and interrogation unit 27. The recording equipment allowing the operational adaptation of the apparatus to varying sizes of products and the conveyors T, T′ might usefully be equipped with encoders to transfer to the unit 26 appropriate position and phase data for facilitating the predisposition of this apparatus for correct automatic operation.

[0012] If the length of the product P is less than the existing distance between axles LM (FIG. 2) of the toothed pulleys operating the belts 10, 110 of the devices A and A′ involved, these devices are placed opposite one another mirrorimage fashion as in FIGS. 2 and 3, so that the axles of the pulleys of the conveyors T of one device are aligned with those of the pulleys of the conveyor T′ of the other device. The apparatus works in the following way. While the bar 19 of device A is placed behind a product P fed in phase by appropriate means to the apparatus, the bar 19‘of device A’ has given up or is about to give up the product P′ which it has previously placed in workstation K, e.g. in a packaging station and this bar 19′ is raised and starts the return course with a speed that is also different from or even higher that of the forward travel movement, and when the same bar 19′ has reached the end of the return course, it may possibly slow down or stop awaiting a subsequent product to pick up and feed to the said station K. Since the bar completes the return movement cyclically, it must not interfere with the product P moving forward in the channel C due to the thrust effect exerted by the other bar, suitable means (not illustrated) could be provided to regulate the vertical position of the apparatus concerned in relation to the bottom of the transport channel C shown in FIG. 1 upon variation of the height of the products. The bar 19, which is low, pushes the relevant product P in the channel C and, at the end of this, places it in the station K which takes delivery of this product and makes it move forward at an identical linear speed. This transfer is completed after the bar 19 starts the rising movement with the return of the relevant connecting rod 17 around the axles of the pulleys 30, 130, so that due to the horizontal deceleration occurring in this return phase, the same bar is moved away from the transferred product and is therefore removed without interference with this product—interference which is at least mitigated in the initial part, from the possibility of that same bar 19 of revolving freely around itself since it is comprised of an idle roller.

[0013] If the product length LP (FIG. 6) is greater than the distance between axles LM mentioned previously (FIG. 2), the runner 25 of the device A′ (FIG. 1) is acted upon to move it forward appropriately in comparison with the other device A, up to the maximum and theoretical condition shown in FIGS. 5 and 6, where the pulleys 30′, 130 of the device A′ are aligned axially with those 3, 103 of the device A, so that the bar 19‘of the device A’ transfers the product in phase to the transom 19 of the device A, which in turn places the same product in the packaging station K in phase. If the length of the straight branches of the conveyors T, T′ is of the order of, e.g., 280 mm, with the devices A and A′ arranged as in FIGS. 5 and 6, it is possible to work on products with a length of up to some 500 mm.

[0014] From FIG. 1 it is apparent that the bar 19‘of the device A’ is fixed to the relevant lower end of the connecting rod 17′ so as to be raised more than the bar 19 of device A, on account of which when the product reaches the position shown by P′ and with the dashed sign in FIG. 6, the bar 19 of the device A is placed beneath that 19‘of the device A’; the lafter may thus freely rise during the return on the final pulleys 30′, 130‘of the conveyor T’ without interfering with the bar 19 which remains in contact with the product to be placed in the said station K.

[0015] The protection of this patent application is also extended to the variant in which the apparatus is reversed compared with the solution shown, so that the thrust bars 19, 19′ carry out the return movement below the products guide channel C. 

1) Variable pitch apparatus for the thrust and phase feed of products to a subsequent workstation, characterised by comprising two thrust bars (19, 19′) placed transversely on the products feed channel (C), fixed to overhang the relevant straight conveyors (T, T′) with identical characteristics, connected to two opposite sides of the said channel, parallel to it, operated in correct phase by driving means such that in covering the outbound branch of the said conveyors, the said bars are arranged alternately and one at a time behind the products being fed in the correct phase in the said channel to determine the movement forward by thrust of the said product and to place it in the workstation (K), after which the bar which has been active, curving around at the final end of the relevant conveyor and being transferred to its return branch, is removed from the said channel and product flow and effects an inverse movement to arrange itself for the repetition of a new work cycle. 2) Apparatus in accordance with claim 1), characterised by the fact that when the length of the products to be handled is less than the length of the active branches of the conveyors (T, T′) for operating the thrust bars (19, 19′), the return pulleys of these conveyors are aligned transversely to the flow of products and the same conveyors are operated so that their bars (19, 19′) alternate in taking the products, moving them forward and placing them in the workstation (K). 3) Apparatus in accordance with claim 1), characterised by the fact that the length of the active branches of the conveyors (T, T′) for operating the thrust bars (19, 19′) is less than the maximum length of the products which this apparatus must be able to feed in phase to the workstation (K) and means are provided to be able to make one of the devices (A′) forming the apparatus to slide longitudinally in comparison with the other which remains fixed in working together with the workstation (K), to advance and move this device longitudinally compared with the other when the length of the products exceeds that of one active branch of the said conveyors (T, T′) so that the distance between the start of the active branch of the conveyor (T′) of the advanced device (A′) and the end of the active branch of the conveyor (T) of the downstream device (A), is from time to time greater and proportionate to the length of the products, provision being made that these conveyors (T, T′) are moved by relevant driving means so that the bar (19′) of the advanced device (A′) picks up in phase the products which are fed in the correct phase to the apparatus and cause them to move forward by thrust and transfer in phase to the thrust bar (19) of the downstream device (A), which further moves the products forward and places them in phase in the workstation (K). 4) Apparatus in accordance with claim 3), in which the thrust bar (19′) of the device (A′) which may be positioned in advance compared with the other device (A′) is arranged so as to follow at least its own active course at a distance from the bottom of the products guide channel (C) which is different and, for example, greater than that existing between the bottom and the thrust bar (19) of the downstream device (A), so that the bar (19′) of the upstream device (A′) gives up the product at the end of its own active course without interfering with already active bar (19) of the downstream device (A). 5) Apparatus in accordance with the preceding claims, characterised by the fact that the conveyors (T, T′) of the two recircling devices forming the apparatus are moved by relevant motive power sets (8, 8′) equipped with respective motors with electronic speed and phase control, e.g. brushless motors, connected to a processing unit (26) equipped with at least one input to collect the related phase signals from the upstream and/or downstream devices of the same apparatus and which is connected to a programming and interrogation unit (27). 6) Apparatus in accordance with the preceding claims, characterised by the fact that the support plates (1, 1′) of the conveyors (T, T′) of the two recircling devices forming the apparatus are mounted on respective support frames (24, 24′) with the mediation of horizontal guides and runners (23, 123 and 23′, 123′) orthogonal to the active branches of the said conveyors and connected to respective manually or remotely controlled means of operation, all so as to be able to vary the transverse distance between the devices to adapt it the variations in the width of the products (P) to be handled. 7) Apparatus in accordance with the preceding claims, characterised by comprising possible means to be able to adjust the relative vertical position of the same apparatus and the products guide channel (C) for the adaptation of the same apparatus to products (P) of different heights. 8) Apparatus in accordance with the preceding claims, characterised by the fact that the plate (1′) of the device (A′) which may be set in advance of the other device (A) is also mounted on a support frame (24′) with the mediation of a guide and runner set (25, 125) parallel to the product feed channel (C) and connected to relevant manual or remotely controlled means of operation. 9) Apparatus in accordance with the preceding claims, in which the two devices (A, A′) comprising this apparatus and the relevant adjustment equipment allowing its operational adaptation to products of different dimensions are equipped with encoders connected to a processing unit (26) governing the motors (8, 8′) of these devices in phase. 10) Apparatus in accordance with the preceding claims, in which the thrust bars (19, 19′) are each composed of an idle roller. 11) Apparatus in accordance with the preceding claims, in which means are provided in such a way that from the time when the front face of a product fed by a thrust bar (19, 19′) of this apparatus reaches the workstation (K) until the complete transfer of that product to such a station, the linear forward speed of the said bar is equal to that of this workstation (K). 12) Apparatus in accordance with the preceding claims, in which each device (A, A′) composing it comprises a vertical support plate (1) placed on one side of the product travel channel (C) and which, on the side turned towards the channel and above it, provides support for the revolution the toothed return pulleys (3, 103, 30, 130) of a pair of toothed belts (10, 110) laid on top of them, appropriately spaced and also parallel vis-à-vis the said channel, one pair of the said pulleys (30, 130) being mounted to revolve freely on a support (11) attached to the said plate with the possibility of adjustment to allow tensioning of the above-mentioned belts, while the axles (2, 102) of the other pair of pulleys (3, 103) traverse the said plate (1) and on its external side identical toothed pulleys (4, 104) are keyed on which a belt (5) controlled by a tensioner (6) is returned and also returned on a toothed pulley (7) keyed to the motive power set axle (8) flanged on a fixed bracket (9) on the external face of the said plate (1), there being at points aligned vertically of the straight upper or lower branches of the said belts fixed supports with transverse pins (16) protruding from the side of the said belts which is opposite that turned towards the said plate and which are rotatably fixed to a vertical connecting rod (17) which at its end has the thrust bar (19) fixed to overhang placed transverse to the product feed channel (C). 13) Apparatus in accordance with claim 12), in which the end (117) of the vertical connecting rod (17) supporting the thrust bar is tapered, is equipped with holes placed one following the other and the said bar (19) protrudes partly from the front of the said connecting rod which is turned towards the workstation (K) to which the products must be fed in phase. 14) Apparatus in accordance with claim 12), in which the said vertical connecting rod (17) is of flat form, is made of light alloy and/or may be equipped with is structural lightening holes (18). 15) Apparatus in accordance with claim 12), in which the vertical connecting rod (17) supporting the thrust bar (19) runs in horizontal and parallel guides (20, 120) linked to brackets (21, 121) fixed to overhang at the top and at the bottom of the support plate (1) of each device (A, A′). 16) Apparatus in accordance with claim 15), in which surfaces (22) of low friction coefficient material are provided between the vertical connecting rod (17) and the relevant guides (20, 120) to limit sliding friction between the parts. 